Number of Years, Months, Weeks, Days, or Hours in a zoo Object

Generic functions for computing the temporal span covered by a zoo object, expressed as years, months, weeks, days, or hours.

Usage

nyears(x, ...)
nmonths(x, ...)
nweeks(x, ...)
ndays(x, ...)
nhours(x, ...)

# S3 method for class 'zoo'
nyears(x, only.integer.output=FALSE, tz, verbose=TRUE, ...)
# S3 method for class 'zoo'
nmonths(x, only.integer.output=FALSE, tz, verbose=TRUE, ...)
# S3 method for class 'zoo'
nweeks(x,
                     week.grouping="calendar",
                     verbose=TRUE, ...)
# S3 method for class 'zoo'
ndays(x, only.integer.output=FALSE, tz, verbose=TRUE, ...)
# S3 method for class 'zoo'
nhours(x, only.integer.output=FALSE, tz, verbose=TRUE, ...)

Arguments

x: A zoo object with a regular time index.
only.integer.output: logical; if FALSE (default), decimal values are returned when the last year, month, day, or hour is not complete. If TRUE, only the number of whole years, months, days, or hours is returned, and a warning is issued when the last period is incomplete.
week.grouping: character indicating how weeks are counted by nweeks. Valid values are:
-) calendar: distinct calendar year-week groups defined by %Y-%W. Weeks crossing a calendar-year boundary are split.
-) sequential: consecutive 7-day groups starting at the first date in x. This argument is fully compatible with daily2weekly.
tz: character, indicating the time zone in which the time index of x is located. If missing, the time zone stored in the index is used when available. See isComplete.
verbose: logical; if TRUE, informative messages are shown in the screen. The functions call isComplete and, when x has missing date/time values, they are reported by isComplete.
...: further arguments passed to or from other methods.

Details

The returned value is computed from the first date/time to the inferred end of the last observation. The end of the last observation is inferred from the regular time step of x. For example, a daily object from 2020-01-01 to 2020-01-31 returns 1 month and 31 days.

Before computing the temporal span, the functions call isComplete(x, out.type="all"). Therefore, incomplete objects are still accepted when their time index has a regular frequency, but missing date/time values are reported when verbose=TRUE.

For nweeks, the result is the number of weekly groups that daily2weekly would produce with the same week.grouping.

Value

A numeric value with the temporal span of x expressed in the requested unit. nweeks returns the integer number of weekly groups. For the other functions, an integer value is returned when only.integer.output=TRUE.

Author

Mauricio Zambrano-Bigiarini, mzb.devel@gmail.com

Examples

dates <- as.Date("2020-01-01") + 0:30
x <- zoo::zoo(seq_along(dates), dates)

nyears(x, verbose=FALSE)
#> [1] 0.08469945
nmonths(x, verbose=FALSE)
#> [1] 1
nweeks(x, verbose=FALSE)
#> [1] 5
ndays(x, verbose=FALSE)
#> [1] 31
nhours(x, verbose=FALSE)
#> [1] 744

y <- x[1:15]
ndays(y, verbose=FALSE)
#> [1] 15
ndays(y, only.integer.output=TRUE, verbose=FALSE)
#> [1] 15